Flagging Inland Data - Explore Grossrange

Summary

CMAR has collected data on several inland bodies of freshwater in Nova Scotia through the wild Atlantic salmon river monitoring project. In addition, CMAR has data collected on several freshwater lakes (e.g. Piper Lake), which is currently published through the Water Quality branch of the Coastal Monitoring Program.

CMAR intends to process and republish all inland data under a new “Inland” branch of the Coastal Monitoring Program. Data will be processed in a similar manner to the water quality data, and data flags will be applied using the qaqcmar package.

It is suspected that sensors on some rivers were out of the water for some period of time during the deployment. Data flagging efforts will flag data for periods of time sensors were suspected to be exposed. During the periods in which sensors were exposed to air, recorded temperatures fluctuate more quickly than when sensors are submerged.

The purpose of this document is to help CMAR determine appropriate data flagging tests and thresholds for freshwater (inland) data. We do not currently have enough freshwater data to conduct as thorough an analysis as was done on the saltwater water quality data to develop tests and thresholds, so thresholds may be picked in more subjective ways.

Waterbodies in dataset:
 [1] "Round Hill River"   "Meteghan River"     "Salmon River"      
 [4] "Liscomb River"      "Musquodoboit River" "Gold River"        
 [7] "LaHave River"       "Mersey River"       "Grand River"       
[10] "Roseway River"      "Middle River"       "North River"       
[13] "Tusket River"      
Stations in dataset:
 [1] "Round Hill River 1"   "Round Hill River 2"   "Round Hill River 3"  
 [4] "Meteghan River 1"     "Meteghan River 2"     "Meteghan River 3"    
 [7] "Salmon River 1"       "Salmon River 2"       "Liscomb River 1"     
[10] "Liscomb River 2"      "Musquodoboit River 1" "Musquodoboit River 2"
[13] "Musquodoboit River 3" "Gold River 2"         "LaHave River 1"      
[16] "LaHave River 2"       "LaHave River 3"       "Mersey River 2"      
[19] "Mersey River 3"       "Grand River 1"        "Grand River 2"       
[22] "Grand River 3"        "Roseway River 1"      "Roseway River 2"     
[25] "Middle River 1"       "Middle River 2"       "Middle River 3"      
[28] "North River 1"        "Tusket River 1"       "Tusket River 2"      
[31] "Tusket River 3"      
Stations which may have experienced air exposure:
  • Liscomb 1
  • Liscomb 2
  • LaHave 2
  • Mersey 2
  • Tusket 3
  • Possibly Musquodoboit 1 and 2

Station Locations

Approximate location of stations included in analysis.

Plot all Station Data

Plot Cleaned Station Data

Suspected outliers have been removed from the following datasets:

  • Liscomb 1
  • Liscomb 2
  • LaHave 2
  • Mersey 2
  • Tusket 3

Distribution of Observations

Summary Stats

By Station

Pooled

Mean and Standard Deviation

Quantiles

Calculate user grossrange threshold

Since the datasets are all normally distributed, mean + SD will be used to develop the grossrange thresholds. Stations have similar mean + SD, so data has been pooled to determine one threshold to be used to flag all inland river datasets.

Mean_sd threshold table

The statistically derived thresholds may be misleading when applied to future dasets, because most of the training datasets do not unclude data from the full year. Thus, for now I recommend CMAR chosen grossrange thresholds until more data is available.

The chosen user minimum threshold is 0 degrees C to identify times during which ice formation may be possible in freshwater inland datasets.

The chosen user maximum threshold is 28 degrees C which is an upper tolerance limit for salmonids (Elliott, 1991; Breau et al., 2011)

Apply user grossrange threshold

Visualize flagged data

Mean_sd

#References Breau, C. et al. (2011). Behaviour during elevated water temperatures: can physiology explain movement of juvenile Atlantic salmon to cool water? J Anim Ecol, 80(4), 844-853. doi:10.1111/j.1365-2656.2011.01828.x

Elliott, J. M. (1991). Tolerance and resistance to thermal stress in juvenile Atlantic salmon, Salmo salar. Freshwater Biology, 25, 61-70.